"As we discover in the final chapter, Maria realized that she has been misled by Leslie and decides to call off the wedding". This sentence is not grammatically correct. To preserve parallel verb tenses, "realized" should be "realizes".

The main character in John Updike's latest (book was published this past summer is a teenager who lives) in New Jersey. The correct version is: "book, which was published this past summer, is a teenager who lives".